Believe it or not, there was a time when every light truck built didn’t have four-wheel drive. In the days following World War II, General Motors didn’t even offer a factory built four-wheel-drive light truck. Instead GM relied on a small vendor called NAPCO or Northwestern Auto Parts Company to give its trucks the all-road and off-road capability needed to compete with the likes of Willys products and Dodge Power Wagons. Studebaker also used NAPCO conversions as did Ford. NAPCO’s ingenious Powr-Pak 4 x 4 conversion allowed a mechanic to transform a two-wheel-drive GM truck into a four-wheel-drive in just a few hours with no welding and minimal cutting needed. The front drive axle in the kit was fitted with tubes modified for constant velocity joints thus allowing the wheels to steer. The transfer case was a divorced unit, driven via a shaft off the transmission. NAPCO conversions date at least as far back as the Advance Design series light trucks, but prior to 1955, only one ton and three-quarter ton GM light trucks could be converted. GM’s 1947-1955 half-ton trucks used a torque-tube style driveshaft that wasn’t easily adapted to a transfer case. Once the torque tube was eliminated in the second-series 1955 trucks, it was possible to use NAPCO conversion kits on half-tons. NAPCO conversions were originally performed by Chevrolet dealers or NAPCO franchises. Starting in 1957, Powr Pak 4×4 was offered as a factory installed option on Chevrolets while GMC offered it from the factory in 1956. This continued until the introduction of the redesigned 1960 trucks when GM used its own four-wheel-drive system on light trucks. On GM factory-built NAPCO 4x4s, you won’t find any NAPCO badges on the exterior. However, you should find NAPCO cast into the front axle. This NAPCO-converted 1956 Chevrolet 3100 for sale on Hemmings.com is an shining example of the breed, restored, it appears to concours condition. From the seller’s description:

1/2 Ton Shortbed Big Back Window with the extremely rare Napco 4-wheel drive. The truck went through a 100 percent complete frame-off restoration. All original drivetrain was rebuilt. Has deluxe heater, original radio, day/night mirror, 16″ Rims.

momentum is huge when it comes to truck’s and I know ‘cuz I try to get my belly dumps to come in at a good rate thru the loose sand on a fill job. the guys that don’t get bogged down and I gotta go get ‘em and push them most of the way thru it. it’s easier on the truck but some guys need convincing. one guy was told to leave unless he stood on it. he did and he learned from it.

Yep. That’s how you did it, unless you might have been so lucky to have a ratcheting differential, i.e. a locking diff. I remember the first winter my dad had his first GMC 4 wheel drive pickup. We had freezing rain and then sub zero temps. A good set of chains was of more use than the 4wd was. I always used to tease my dad that it was good for going 100 feet farther before it got stuck.

Thanks to Mr. McNessor again for giving me my “truck fix”. I look at this truck, and see how “modernized” it is. Truth is, these trucks never looked like this, and were relegated to extreme duty right from the start. The only reason someone would shell out the extra dollars ($995 dollars, not including labor, according to Wiki) is so they could plod through the brush and bounce off of small trees, to get to remote destination, and not to get to Walmart on a snowy day to get eye make-up( or whatever).
I wasn’t aware of Ford using NAPCO, if they did, it wasn’t for long. Ford used Marmon-Herrington 4 wheel drive set-ups from the late ’40′s through the late ’50′s. I’ve driven original vehicles like this, and make no mistake, they are a handful, far from the 4 wheel drives of today.
Beautiful truck!

Hi Howard. I echo your comments all the way, including thanks to Mike for the eye candy. I too wasn’t aware that Ford used Napco conversions; I thought that Ford and Marmon-Herrington collaborated on a lot of 4x4s since the late 30s.

My dad bought one of the first 4x4s in our town. It was a ’56 International S-120 (which is still in use today). It spent more time in the shop than in use on the farm so, thinking that 4x4s weren’t well built, Dad traded it for an ordinary 3/4 ton. The guy who bought it thought it was the best invention since the Vikings invented meade. When the new 3/4 ton found its way into the repair shop countless times, Dad finally figured out that the ranch foreman was the one who broke everything.

Very nice truck here! But I can think of a lot better place for it to reside…

When I was a little boy( I was 6 at the time this truck was new)I always had a eye for a different looking vehicle, like a Brinks armored car, or a hearse (scary to me I didn’t like seeing them in front of funeral parlors—baby caskets terrified me for some reason,like I was NEXT UP !!). The tall 4X4 trucks were the Ultimate Coolmobiles. I loved trucks, and seeing them go through the deep snow in Chicago like nothing, while everyone else had to shovel themselves out had to be the “wow” factor. “Gotta get me one of them”. I did; in 1979, a Brand New Cherokee Golden Eagle 4X4 Black 360 auto. 4X4′s ever since. I still love those old “Tall/Boys”.I liked the Marmon Herrington Fords too. Thanks for letting us see these fine trucks once again with some basic tech info.. Hemmings just “Keeps On Truckin” !

Lot’s of rural fire departments bought these.Decked them out to fight grass and brush fire’s.
A local radio personality that ran A automotive talk show had one in the Twin Cities area several years ago.